化学兴趣小组的同学发现实验台上一瓶标签破损的无色溶液（标签如图）．他们提出可能是Na₂SO₄、NaHCO₃、Na₂CO₃溶液中的一种，于是决定对这瓶溶液进行实验探究．查阅资料：三种物质溶液在常温下的pH如下表

增加：在缺词处加一个漏字符号（∧），并在其下面写出该加的词。

删除：把多余的词用斜线（\）划掉。

修改：在错的词下划一横线，并在该词下面写出修改后的词。

    Last Saturday afternoon, a charity sale held on our school playground. Although it was no easy task, students active participated in it.

    To organize it successfully, we' made full preparations. After the sale, from the students we collected variously second-hand goods which were still in good condition and classify them. Then came the big day. With all the teachers and students involve, the activity turned out to be successful. We raised 5,000 yuan for total at the end of the activity. All the money we raised up will go to the students from poor family to help finish their studies. It's so a meaningful activity that students look forward to the next charity sale.